Wastegate Dump Question

Post by **rn240sx** » Mon Mar 20, 2006 5:11 pm

I posted this on another forum as well to get more replies. But my question is this, has anyone in the past or currently been able to prove that running a closed wastegate dump ( recirculating it back to the exhaust stream) can cause hp loss..?? Or running open dump will add more power.. I dont see how, but if that theory is correct, please expain this to me so that i can understand how this is true. I do know what if the angle of the dumps entry back into the exhaust stream is too large (more than 45 deg) then it will cause boost creep. That ive been there dont that and its been fixed.

Post by **WDRacing** » Mon Mar 20, 2006 5:19 pm

Ok, as a rule of thumb the more free flowing the exhaust can be the better it is. Plumbing a return from the wastegate into the downpipe cloe to the turbo itself can cause a disturbance in the flow. Having the angle of the return pipe into the exhaust at a steep angle can cause flow disturbance also.

So having the WG vented to the atmosphere is the best route because it disturbs nothing and actually gives another channel for the exhaust to flow. More flow equals more power when it comes to anything forced induction.

Hope that makes sense. I had to retype a bunch of it cause I couldn't even read my own thoughts...

WD

Post by **rn240sx** » Mon Mar 20, 2006 5:38 pm

WDRacing wrote:Ok, as a rule of thumb the more free flowing the exhaust can be the better it is. Plumbing a return from the wastegate into the downpipe cloe to the turbo itself can cause a disturbance in the flow. Having the angle of the return pipe into the exhaust at a steep angle can cause flow disturbance also.

So having the WG vented to the atmosphere is the best route because it disturbs nothing and actually gives another channel for the exhaust to flow. More flow equals more power when it comes to anything forced induction.

Hope that makes sense. I had to retype a bunch of it cause I couldn't even read my own thoughts...

WD

Ok, im sitting here trying to think about what u wrote and understanding that if there is no disturbance to the turbine's exhaust flow that it will help to create more power... I still dont understand how that that effects power output. I was told that the less restrictive the exhaust stream is, the faster the spool which is completely understandable....But how that helps add more power..... im still blank......

Post by **LEMHEAD16** » Mon Mar 20, 2006 5:44 pm

I think WD is right on as far as flow goes.

To me it all depends on what type of car it is. On a race car I would definatly run an open dump possible more power and less plumbing.On a Daily driver I would route it back into the exhaust. On a daily basis the open dump is so dang loud it got really irritating to me quick.

I routed my wastegate back into the exhaust at the second bend and have had no problems thus far running 10 psi.

Post by **C-Kwik** » Mon Mar 20, 2006 6:06 pm

What it ultimately comes down to is backpressure. A pipe of a certain size will move a certain amount of air at a certain speed. When you add more air the pressure increases in order to be able to move the larger volume of air. And as this additional air is merged in from the dumppipe, it creates some turbulence which disturbs airflow and ultimately requires additinal pressure to overcome.

The airflow through a turbine is carried by the pressure differential across the turbine. To move any gas or liquid through an orifice, the pressure on one side has to be higher than the pressure on the other. To move a given volume of gas through a turbine, the pressure differential must be the same. Basically, if you increase pressure behind the turbine, you can decrease pressure proportionately in front of it and have the same boost effect. This means more air an be diverted through the wastegate. Furthermore, if you have an open dump, the air escaping through the wastegate has a cleaner path ultimately reducing restriction to the motor.

Post by **WDRacing** » Tue Mar 21, 2006 5:40 am

Thanks Chano, I couldn't manage to explain that...lol.

Post by **C-Kwik** » Tue Mar 21, 2006 9:53 pm

Anytime

Post by **rn240sx** » Sat Mar 25, 2006 2:45 pm

It will only take a few minutes to run open dump but the only problem with that is i will have an exhaust leak on the downpipe where the dump entered into it. I dont have any means of sealing that 1.5 inch pipe. The proper way would be to cut that pipe off, and get a sheet of metal to cover the opening and weld it shut. But i dont have that stuff so i will have to run closed dump for now...

Post by **C-Kwik** » Sun Mar 26, 2006 5:15 pm

Honestly, if you don't care about the marginal HP gains (I couldn't tell on mine, but had pretty smooth re-entry), then just run the closed loop system and call it a day. I originally had an open dump, but had it routed back in as it sounded like crap. Then again, some people seem to like it.

Post by **rn240sx** » Sun Mar 26, 2006 5:49 pm

I just wana see if it feels any faster.

At 1st i was running open dump and it was just plain loud and horrible. It only lasted 2 weeks b4 i routed it back into the exhaust stream. Then it was nice and quiet and i was happy.

Lots of people here love that open dump on the wastegate.... But we all have our preferences...

Wastegate Dump Question

Wastegate Dump Question

Re: (WDRacing)

Re: (C-Kwik)

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